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Colon Cancer

Colon Cancer is also referred to Colorectal Cancer or Cancer of the Large Bowel. The areas that can be affected are: Colon, Rectum, and Appendix.

Deaths related to colon cancer are above 650,000 per year worldwide. It is the fifth most common form of cancer in the U.S.

Colon Cancer in the bowel often begins from polyps referred to as Adenomatous polyps. Over time – some of the polyps can become cancerous. Polyps appear as mushroom-shaped and are usually non-cancerous [benign]

Colonoscopy is usually the primary mode of diagnosis. But prevention of cancer is extremely important and a colonoscopy is recommended in all adults by the age of 50.

There were an estimated 100,000 new cases of colon cancer and nearly 40,000 rectal cancers in the United States in 2013. There were just over 50,000 deaths of both colon and rectal cancer.

The main symptoms are blood in stool, change in bowel movement, weight loss, and fatigue.

Potential Symptoms:

–  Abdominal pain
–  Constipation
–  Diarrhea
–  Smaller stools
–  Blood in stool – bright red
–  Black stools – older blood
–  Increased mucus in stool
–  Vomiting
–  Abdominal Distension
–  Lack of iron – anemia
–  Loss of weight
–  Loss of appetite

Risk Factors:

–  7% risk of getting colon cancer within your life

1.)  Age – Occurs more often in 60s and 70s
2.)  Diet
3.)  Smoking
4.)  Physical inactivity or low activity
5.)  History of cancer
6.)  Genetics

–  Family History of colon cancer  – especially when cancer occurs in the family member under the age of 55
–  Familial adenomatous polyposis  –  nearly a 100% chance if untreated

7.)  Polyps
8.)  Virus

– Human Papillomavirus

9.)  Alcohol – may be a risk factor in heavy doses
10.)  Environmental factors
11.)  Exogenous hormones – [though little evidence]

Causes:

–  Cancer starts in the epithelial cells of the colon or rectum
–  Mutations are often seen of the Wnt signaling pathway
–  Many different proteins may have a mutation
–  Some mutations are inherited while some are acquired
–  Often takes years for colon cancer to progress
–  Earlier the diagnosis the better the prognosis

Staging

Stage 0  –  Tumor only in mucosa [Cancer-in-situ]

Stage 1 –

T1:  Tumor enters submucosa
T2:  Tumor enters muscularis propria

Stage II-A Tumor enters subserosa or deeper, no organs involved

Stage II-B  Tumor enters adjacent organs

Stage III-A  Tumor and metastasis to 1-3 regional lymph nodes

Stage III-B  Tumor and metastasis to 4 or more regional lymph nodes

Stage III-C  Tumor and distant metastasis present

Diagnosis

–  Digital Rectal Exam
–  Fecal Occult Blood Test
–  Sigmoidoscopy – Flex Sig
–  Colonoscopy
–  Standard Computed Axil Tomography
–  Virtual Colonoscopy
–  Barium enema
–  Blood work
.  Carcinoembyronic antigen [CEA] is a protein found in most all colorectal tumors.

Prevention

1.) Early awareness

2.) Colonoscopy by age 50 unless family history

3.) Repeat Colonoscopy every 5 – 10 years if normal

4.) Abnormal colonoscopy will change the follow-up visit

Lifestyle and Nutrition

–  Limit: overeating, sedentary and high red or process meats
–  Increase:  Physical Fitness, good nutrition, dietary fiber

Calcium

–  May or may not provide some degree of prevention

Aspirin

–  Should not be taken to prevent Colorectal cancer

Treatment

Surgery

–  In early stages surgery can be curative in some individuals
–  Removal of polyps during colonoscopy
–  Surgical removal of section of colon affected
–  Removal of regional lymph nodes may be necessary

Chemotherapy

–  May be applied after surgery
–  May be the only form of treatment available in certain cases

.  Cetuximab  (Erbitux)
.  Panitumumab  (Vectibix)
.  5-fluorouracil  (5-fu)
.  Capecitabine  (Xeloda)
.  Leucovorin  (LV, Folinic Acid)
.  Oxaliplatin  (Eloxatin)
.  others

Radiation

  –  Not often used

  –  Can lead to “radiation enteritis”

  –  Can be used more in rectal cancer

Palliative treatment

*** – non currative

Investigated Treatments

  –  Cancer Vaccine – TroVax

  –  Immunotherapy with Bacillus Calmette-Guerin

  –  Chemotherapy